Researchers made the discovery during a study of typing skills in which more than 37,000 volunteers from 160 countries took a speed and accuracy test on their mobile phones.

People who tapped out messages with a single finger managed on average only 29 words per minute (wpm), but those who mastered the two-thumb technique hit a blistering 38wpm, only 25 percent slower than an average typist on a full-sized Qwerty keyboard.

One volunteer thumbed out sentences on their mobile phone at a blur-inducing 85wpm, far exceeding the 52wpm that people typically reach on a standard keyboard. While the study involved participants from around the world, the majority were women in their 20s and about half were Americans.

People who could remember when mobile phones were only good for phone calls were considerably slower than younger users, the study suggested. Teenagers tapped out sentences at an average of about 40wpm, while those in their 40s and 50s managed only 29wpm and 26wpm.

Anna Feit, a co-author of the study and computer scientist at ETH Zurich in Switzerland. “We showed, at a large scale, that people who type using both thumbs are very much faster than those who use just one finger.”

The scientists found that autocorrect improved typing speeds by nearly 9wpm, but word prediction slowed people by 2wpm, distracting them and making them choose suggested words.